<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    a{
      text-decoration: none;
    }
    a:hover{
      text-decoration: underline;
    }
    p{
      color:red;
      /* background-color: blue; */
    }
    p:hover{
      color:blue;
      
    }
    li{
      list-style: none;
    }
  </style>
</head>
<body>
  <a href="#">baidu</a>
  <p>
    helloworld
  </p>
  <ul>
    <li>aaaa</li>
    <li>bbb</li>
    <li>ccc</li>
  </ul>
</body>
</html>